In general, a blade assembly of a rotation drum type electric razor includes a main body, a motor which is disposed on a center axis of the main body, and a power transmission mechanism which transmits rotational force of the motor to a driving shaft of the blade assembly. A cover having a protective screen is provided at an upper side of the blade assembly.
In a conventional blade assembly 1, as shown in FIG. 1, a plurality of blade lines 3 are spirally formed on an outer surface of a cylindrical body 2 formed of a metal material, such that a shaving operation is carried out at a space between the blade line 3 and the protective screen.
A driving shaft 4 is inserted into a center portion of the cylindrical body 2, and a driven gear is provided at both ends of the driving shaft 4 so as to receive driving power from a power transmission mechanism. The blade line 3 is integrally formed with the surface of the metallic cylindrical body 2 formed by an insert injection molding method, and a separate metallic SUS blade is installed on the outer surface of the cylindrical body 2 so as to perform the shaving operation along with the blade line 3.
In the conventional blade assembly of the rotation drum type electric razor, the blade line is integrally formed on the outer surface of the cylindrical body formed by the insert injection molding method so as to perform the shaving operation together with the separate SUS blade. However, since there is not provided a cutting angle, cutting efficiency is deteriorated. Further, since the blade line has a short length, a cut beard is caught between the blade lines.
Furthermore, since the conventional rotation drum type electric razor is provided with only one cylindrical blade assembly, and body hair is cut only at an uppermost point of the cylindrical blade assembly, the ability of cutting the body hair is lowered. And also in order to carry out the clean shaving operation, it is necessary to repeatedly perform a serial process of contacting the uppermost point of the cylindrical blade assembly with a portion to be shaven and then cutting the body hair, and thus shaving time is increased, and also it makes a user tired and inconvenient.
In addition, if the conventional rotation drum type electric razor is used for a long period, the protecting screen disposed at an outer side of the blade is deformed into a space between the adjacent blades by the user's external force, and the deformed screen is interfered with the blade rotated at a high speed, thereby deteriorating the shaving efficiency.